A paint ball gun includes a barrel, a bullet ejector, a body, a valve set, a striker and a trigger. The barrel is in communication with the body so that air can go into the barrel from the body. The bullet ejector is movable in the barrel. The valve set is disposed in the body so that the air can only go into the barrel from the body through the valve set. The valve set includes a plunger movable in a housing. The striker is movable in the body. The trigger is operable to make the striker strike the plunger so that the air can go through the housing. The striker is generally made of hard metal since it has to take recoil. There are however problems with the striker. Firstly, it is heavy and expensive. Secondly, it requires a large force to actuate the striker, and the recoil is therefore large.
The present invention is therefore intended to obviate or at least alleviate the problems encountered in prior art.